1. Field of the Invention
The present invention relates to a system for adjusting an axis of a transmitter and receiver mounted on a moving body, wherein the transmitter and receiver transmits a detection signal toward a predetermined scanning area and receives, as a reflected signal, the detection signal reflected from an object positioned ahead of the moving body.
2. Description of the Related Art
When a radar used in an adaptive cruise control system (ACC system), a Stop & Go system (congestion tracking system), a vehicle interval alarm system, and other such known systems, is mounted on a vehicle, unless the object detection axis of the radar is correctly directed in a preset direction, such systems are known to malfunction as a result of erroneously detecting an oncoming vehicle in an adjacent lane, and/or do not function at all as a result of only detecting a road surface, an overpass, or a signboard instead of a preceding vehicle.
Japanese Patent No. 3114849 and Japanese Patent Application Laid-open No. 2000-258527 disclose systems which make the object detection axis of a radar accurately coincide with a preset direction (aiming).
In the system described in Japanese Patent No. 3114849, a radar fixed to a vehicle body transmits a detection signal in a relatively wide preset scanning area. Based on the results detected by the radar using a reference reflecting body placed directly in front of the vehicle body, a detection area in which the reference reflecting body is positioned at the center, is set within the scanning area. At this point, the angle at which the radar is mounted on the vehicle body is not adjusted, but rather, auto aiming is carried out using computer software to set the detection area.
The system described in Japanese Patent No. 3114849 suffers from the problem of necessarily having to set a scanning area that is wider than the detection area in which the object is actually detected to ensure the detection area is set therein, which results in a wasted region in which the object is not actually detected although the object is detectable. For example, when the lateral detection area is 16°, and the angular error of mounting the radar on the vehicle body is ±3°, it is necessary to ensure that the scanning area is 16°+2×3°=22°, wherein 6° (27%) of the scanning area is the wasted region.
In the system described in Japanese Patent Application Laid-open No. 2000-258527, when a deviation of the radar axis relative to the vehicle travel direction is detected, the radar axis is made to coincide with the vehicle travel direction by rotating an adjustment bolt used to mount the radar on the vehicle body.
The system disclosed in Japanese Patent Application Laid-open No. 2000-258527 suffers from the problem of having to manually rotate the adjustment bolt in order to accurately adjust the radar axis, which can be quite a troublesome operation.